AbstractToday’s enormous development challenges are complicated by the reality of climate change—the two are inextricably linked and together demand immediate attention. Climate change threatens all countries, but particularly developing ones. Understanding what climate change means for development policy is the central aim of the World Development Report 2010. It explores how public policy can change to better help people cope with new or worsened risks, how land and water management must adapt to better protect a threatened natural environment while feeding an expanding and more prosperous population, and how energy systems will need to be transformed. The report is an urgent call for action, both for developing countries who are striving to ensure policies are adapted to the realities and dangers of a hotter planet, and for high-income countries who need to undertake ambitious mitigation while supporting developing countries efforts. A climate-smart world is within reach if we act now to tackle the substantial inertia in the climate, in infrastructure, and in behaviors and institutions; if we act together to reconcile needed growth with prudent and affordable development choices; and if we act differently by investing in the needed energy revolution and taking the steps required to adapt to a rapidly changing planet.